They are divided into two parts separated by a single space. Those two parts are the outward code and the inward code. The Blaenau Gwent outward code includes the postcode area and the postcode Winchestown district. The inward code includes the postcode sector and the postcode unit.

If you want to send a mail to Winchestown, you should use the corresponding Postcode. Winchestown Postcode district is NP23 4.